Human B cell maturation antigen also known as BCMA; TR17_HUMAN, TNFRSF17 (UniProt Q02223), is a member of the tumor necrosis receptor superfamily that is preferentially expressed in differentiated plasma cells (Laabi et al. 1992; Madry et al. 1998). BCMA is a non glycosylated type III transmembrane protein, which is involved in B cell maturation, growth and survival. BCMA is a receptor for two ligands of the TNF superfamily: APRIL (a proliferation-inducing ligand), the high-affinity ligand to BCMA and the B cell activation factor BAFF, the low-affinity ligand to BCMA (THANK, BlyS, B lymphocyte stimulator, TALL-1 and zTNF4). APRIL and BAFF show structural similarity and overlapping yet distinct receptor binding specificity. The negative regulator TACI also binds to both BAFF and APRIL. The coordinate binding of APRIL and BAFF to BCMA and/or TACI activates transcription factor NF-κB and increases the expression of pro-survival Bcl-2 family members (e.g. Bcl-2, Bcl-xL, Bcl-w, Mc1-1, A1) and the downregulation of pro-apoptotic factors (e.g. Bid, Bad, Bik, Bim, etc.), thus inhibiting apoptosis and promoting survival. This combined action promotes B cell differentiation, proliferation, survival and antibody production (as reviewed in Rickert R C et al., Immunol Rev (2011) 244 (1): 115-133).
The TCR/CD3 complex of T-lymphocytes consists of either a TCR alpha (α)/beta (β) or TCR gamma (γ)/delta (δ) heterodimer coexpressed at the cell surface with the invariant subunits of CD3 labeled gamma (γ), delta (δ), epsilon (ε), zeta (ζ), and eta (η). Human CD3ε is described under UniProt P07766 (CD3ε_HUMAN). An anti CD3ε antibody described in the state of the art is SP34 (Yang S J, The Journal of Immunology (1986) 137; 1097-1100). SP34 reacts with both primate and human CD3. SP34 is available from PharMingen. A further anti CD3 antibody described in the state of the art is UCHT-1 (see WO2000041474). A further anti CD3 antibody described in the state of the art is BC-3 (Fred Hutchinson Cancer Research Institute; used in Phase I/II trials of GvHD, Anasetti et al., Transplantation 54: 844 (1992)).
A wide variety of recombinant bispecific antibody formats have been developed in the recent past, e.g. by fusion of, e.g. an IgG antibody format and single chain domains (see Kontermann R E, mAbs 4:2, (2012) 1-16). Bispecific antibodies wherein the variable domains VL and VH or the constant domains CL and CH1 are replaced by each other are described in WO2009080251 and WO2009080252.
An approach to circumvent the problem of mispaired byproducts, which is known as ‘knobs-into-holes’, aims at forcing the pairing of two different antibody heavy chains by introducing mutations into the CH3 domains to modify the contact interface. On one chain bulky amino acids were replaced by amino acids with short side chains to create a ‘hole’. Conversely, amino acids with large side chains were introduced into the other CH3 domain, to create a ‘knob’. By coexpressing these two heavy chains (and two identical light chains, which have to be appropriate for both heavy chains), high yields of heterodimer formation (‘knob-hole’) versus homodimer formation (‘hole-hole’ or ‘knob-knob’) was observed (Ridgway J B, Presta L G, Carter P; Protein Eng. 9, 617-621 (1996); and WO1996027011). The percentage of heterodimer could be further increased by remodeling the interaction surfaces of the two CH3 domains using a phage display approach and the introduction of a disulfide bridge to stabilize the heterodimers (Merchant A. M, et al, Nature Biotech 16 (1998) 677-681; Atwell S, Ridgway J B, Wells J A, Carter P., J MoI Biol 270 (1997) 26-35). New approaches for the knobs-into-holes technology are described in e.g. in EP 1870459A1. Although this format appears very attractive, no data describing progression towards the clinic are currently available. One important constraint of this strategy is that the light chains of the two parent antibodies have to be identical to prevent mispairing and formation of inactive molecules. Thus this technique is not appropriate for easily developing recombinant, bispecific antibodies against two targets starting from two antibodies against the first and the second target, as either the heavy chains of these antibodies and/or the identical light chains have to be optimized. Xie, Z., et al, J Immunol Methods 286 (2005) 95-101 refers to a format of bispecific antibody using scFvs in combination with knobs-into-holes technology for the FC part. WO2012116927 and WO2010145792 mention exchanging the CH1 and CL domains. WO2009080254 mentions knob in hole constructs for producing bispecific antibodies. WO 2006093794 relates to heterodimeric protein binding compositions. WO199937791 describes multipurpose antibody derivatives. Morrison, S. L., et al., J. Immunol. 160 (1998) 2802-2808 refers to the influence of variable region domain exchange on the functional properties of IgG.
WO 201302362 relate to heterodimerized polypeptides. WO201312733 relates to polypeptides comprising heterodimeric Fc regions. WO2012131555 relates to engineered heterodimeric immunoglobulins. EP 2647707 relates to engineered hetero-dimeric immunoglobulins. WO2009080251, WO 2009080252, WO 2009080253, WO 2009080254 and Schaefer, W. et al, PNAS, 108 (2011) 11187-1191 relate to bivalent, bispecific IgG antibodies with a domain crossover. The multispecific antibodies with VH/VL replacement/exchange in one binding to prevent light chain mispairing (CrossMabVH-VL) which are described in WO2009080252, (see also Schaefer, W. et al, PNAS, 108 (2011) 11187-1191) clearly reduce the byproducts caused by the mismatch of a light chain against a first antigen with the wrong heavy chain against the second antigen (compared to approaches without such domain exchange). However their preparation is not completely free of side products. The main side product is based on a Bence-Jones-type interaction (Schaefer, W. et al, PNAS, 108 (2011) 11187-1191).
Antibodies against BCMA are described e.g. in Gras M-P. et al. Int Immunol. 7 (1995) 1093-1106, WO200124811, WO200124812, WO2010104949 and WO2012163805. Antibodies against BCMA and their use for the treatment of lymphomas and multiple myeloma are mentioned e.g. in WO2002066516 and WO2010104949. WO2013154760 relates to chimeric antigen receptors (CAR) comprising a BCMA recognition moiety and a T-cell activation moiety.
Ryan, M C et al., Mol. Cancer Ther. 6 (2007) 3009-3018 relate to targeting of BCMA for plasma cell malignancies. Antibody SG1, with ligand blocking activity could promote cytotoxicity of multiple myeloma (MM) cell lines as naked antibodies or as antibody-drug conjugates (ADC). SG1, an inhibitory BCMA antibody, blocks APRIL-dependent activation of nuclear factor-KB in a dose-dependent manner in vitro. Cytotoxicity of SG1 was assessed as a naked antibody after chimerization with and without Fc mutations that enhance FcγRIIIA binding. Ryan also mentions antibody SG2 which does not significantly inhibit APRIL binding to BCMA. However SG2 showed a 20 fold higher IC50 value as SG1 measured as cytotoxic activity of a drug conjugate against BCMA positive myeloma cell lines. Ryan conclude that BCMA antibodies can act on myeloma cell lines through multiple mechanisms that include inhibition of APRIL-dependent NF-κB activation, promotion of tumor cell lysis by natural killer cell-mediated ADCC activity, and induction of cytotoxicity by ADCs.
Bispecific antibodies against CD3 and BCMA are mentioned in WO2007117600, WO2009132058, WO2012066058, WO2012143498, and WO2013072415. PCT/EP2014/052189 and PCT/EP2014/052190 describe antibodies against BCMA and bispecific antibodies against CD3 and BCMA comprising certain CDRs and variable domains disclosed also in the present invention.
Accordingly there is a need for bispecific antibodies against CD3ε and BCMA with VH/VL exchange which can be produced in high yield and easily purified.